Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Accrued Expenses and Other Current Liabilities
Payroll and related costs	$ 4,063	$ 8,927
Employee benefits	4,265	4,113
Accrued warranty	5,504	7,423	$ 5,188	$ 6,279
Other	3,077	5,086
Accrued expenses and other current liabilities	$ 16,909	$ 25,549